PROJECT SUMMARY/ABSTRACT Childhood obesity is a serious and costly health problem in the United States that disproportionately affects economically disadvantaged children living in rural, low-income areas. Despite this, virtually no effective preventive strategies target the childcare setting, where many children eat 75% of their meals. Responsive feeding (RF) practices, which provide structure and limits while allowing the child to exercise some autonomy, foster the development of self-regulation of food intake. RF has been shown to be a promising target of interventions, but these trials have focused primarily on the home environment. Strategies to improve the food environment and promote RF and child appetite regulation in multiple settings are needed. The ONE PATH study will rigorously test the effect of adding RF and appetite regulation components to an existing, evidence-based program that intervenes on the childcare setting environment. An innovative methodological framework, Multiphase Optimization Strategy (MOST), will be used to identify which intervention components improve RF and children?s appetite regulation among rural, low-income children enrolled in Head Start. Using a factorial design, Head Start classrooms (n=48) will be randomized to receive or not receive three components: a) RF training for early childhood education (ECE) providers, delivered via online module; b) RF training for parents, delivered at home by Extension educators; and c) child self- regulation curriculum, delivered in Head Start classrooms. The interventions will take place over the course of one school year (~9 months), spanning three cohorts. Intervention component efficacy will be determined by evaluating caregiver feeding practices and child appetite regulation (primary outcomes) and changes in childcare and home environments, and child BMI z-score (secondary outcomes). This study will yield an optimized intervention comprised of effective and efficient components that will be ?packaged? and tested in a future RCT. The proposed research will improve the evidence base needed to translate lessons learned in the laboratory to community settings where children eat, optimizing the care of preschool-aged children. To successfully complete this study, we have assembled a transdisciplinary team, including researchers, educators, and Extension professionals. Advisory board members will represent the American Academy of Pediatrics (AAP), Penn State Cooperative Extension - Better Kid Care, and Pennsylvania Head Start. Our multi-disciplinary team has a history of working together and are well suited to design and test this multi-site, multi-component intervention. We have experiences implementing interventions in the home and classroom settings, with access to Head Start children in 7 rural counties in Pennsylvania. This application has several unique features/strengths including: public health/clinical significance, targeting RF of ECE providers, engaging parents in ECE care, and using innovative methods to optimize our intervention. This research compliments the over-reaching goal of NIH to improve maternal/child health and it is consistent with the NIDDK mission.